In a pre-show demonstration of the Longhorn graphics subsystem at the WinHEC trade show in New Orleans Monday night, I saw for the first time some of the advanced video effects that Microsoft will enable in the next Windows version. Longhorn, due in late 2004 or early 2005, includes a completely new desktop composition system that replaces the model used in previous Windows versions with one that is more technically advanced, visually appealing, and scalable. The early test versions Microsoft is showing at WinHEC include amazing animation effects, smooth window scaling, and advanced window translucency.

The change is startling. In previous Windows versions, the Windows desktop was rendered as a single display surface and each window is a region on that shared surface. In this model, individual windows are only responsible for drawing their own surfaces, and then only when those surfaces are not hidden by other windows. In Longhorn, each window has its own, full-featured surface, independent of the other windows and each window thinks it is always 100 percent visible, forcing it to redraw itself constantly. Likewise, the desktop is rendered many times a second by combining the contents of each open window. These changes requires significantly more graphics resources than previous Windows versions, of course, but Microsoft notes that most modern PCs have 3D graphics power to spare. For those PCs that don't have the hardware necessary to take advantage of the full Longhorn user experience, Microsoft will scale the graphics back into different modes.